The major aim of this project is to determine if transfusion and overtransfusion leads to extensive net fluid filtration and a disproportionate rise in extravascular fluid volume relative to responses observed in normal saline control animals, and to determine if the magnitude of the fluid efflux, if any, is sufficient in magnitude to be an important determinant of irreversibility. Changes in extravascular fluid volume will be inferred from changes in organ weight and segmental vascular resistances. In this study the effects of transfusion on extravascular fluid volume will be investigated in the gut of anesthetized dogs previously subjected to severe hemorrhagic and endotoxin shock. Responses will be compared to those observed in saline control animals similarly transfused.